Tourbillons for mechanical clocks and clockwork movements have been known for some time. In these, the escape wheel, the pallet lever and the so-called balance of the clockwork movement are arranged in a mobile cage which is coupled with or firmly connected to the arbor of the second wheel, consequently the second pinion. The balance or balance staff typically coincides with an imaginary axis extension of the second pinion in this case. A gear wheel connected to the escape wheel finally meshes with a fixed gear wheel disposed coaxial to the balance staff, so that the tourbillon, and therefore its cage performs one complete rotation per minute.
The accurate setting of a mechanical timepiece requires the second display to be stopped. In conventional movements, this is usually achieved by means of a so-called balance stop which for example can be activated by pulling out a crown, and can be deactivated again by pushing in the crown.
In timepieces with a minute tourbillon, in which the second display is achieved directly by the mobile cage of the tourbillon, the realization of such a balance stop turns out to be extremely difficult and complicated.
A balance stop for a tourbillon is well-known, for example from EP 2 793 087 A1. This comprises a braking element which is capable to be brought into contact with the balance and is movable axially to the balance axis. To match the timepiece with a standard time, it is therefore possible to stop the balance and with that the tourbillon mechanism at any time.